MCU: Pic16F886
Programmer: PICkit4
IDE: MPLAB X IDE v5.40
Assembler: pic-as v2.30 (xc8)
Circuit:
An LED with a 270 Ω resistor on RA0.
3.3k Ω pull-up resistor on MCLRE.
Vdd on pin 20.
Vss on pin 19.
This is the test code I want to debug and step through instruction by instruction:
PROCESSOR 16F886
PAGEWIDTH 132
RADIX DEC
#include <xc.inc>
config DEBUG = ON, LVP = OFF, FCMEN = OFF, IESO = OFF, BOREN = OFF
config CPD = OFF, CP = OFF, MCLRE = OFF, PWRTE = OFF, WDTE = OFF
config FOSC = INTRC_NOCLKOUT, LVP = OFF, BOR4V = BOR40V, WRT = OFF
PSECT StartCode,class=CODE,delta=2
global Start
Start:
movlw 11000000B ;set option register
movwf OPTION_REG
movlw 00100000B ;set the status register (select bank 1)
movwf STATUS
movlw 11111110B ;everything to input except for RA0
movwf TRISA
movlw 00000000B ;set the status register (select bank 0)
movwf STATUS
bcf PORTA, 0 ;clear bit zero in PORTA register
sleep
END Start
When I run the project the code works as expected.
But when I set a breakpoint and hit "Debug Main Project" I get the error: Reception on endpoint 129 failed (err = -10121)
Or it stays in the "build, load" state for minutes until I quit the process if I play around with config settings.
The PIC16886 has an "in-circuit debugger (on board)" according to page 1 of the datasheet and the block diagram.
1 Answer 1
There are a few things that may be the cause of instability in your PICkit4.
The code you posted could be a lot better so here is a custom crafted PIC16F886 assembly language example for you:
;
; File: main.S
; Target: PIC16f886
; Author: dan1138
; Date: 2020年09月29日
; Compiler: pic-as(v2.20)
; IDE: MPLABX v5.40
;
; PIC16F886
; +---------:_:---------+
; VPP RE3 -> : 1 MCLRn PGD 28 : <> RB7 PGD
; RA0 <> : 2 AN0 PGC 27 : <> RB6 PGC
; RA1 <> : 3 AN1 AN13 26 : <> RB5
; RA2 <> : 4 AN2 AN11 25 : <> RB4
; RA3 <> : 5 AN3 AN9/PGM 24 : <> RB3
; RA4 <> : 6 T0CKI AN8 23 : <> RB2
; RA5 <> : 7 AN4 AN10 22 : <> RB1
; GND -> : 8 VSS AN12 21 : <> RB0
; RA7 <> : 9 OSC1 VDD 20 : <- 5v0
; RA6 <> : 10 OSC2 VSS 19 : <- GND
; RC0 <> : 11 SOSCO RX 18 : <> RC7
; RC1 <> : 12 SOSCI TX 17 : <> RC6
; RC2 <> : 13 CCP1 SDO 16 : <> RC5
; RC3 <> : 14 SCL SDI 15 : <> RC4
; +---------------------+
; DIP-28
; Description:
;
; Example project for the PIC16F886 controller using the pic-as(v2.20) tool chain.
;
; Add this line in the project properties box, pic-as Global Options -> Additional options:
; -Wa,-a -Wl,-pPor_Vec=0h,-pIsr_Vec=4h
PROCESSOR 16F886
PAGEWIDTH 132
RADIX DEC
#include <xc.inc>
; PIC16F887 Configuration Bit Settings
; 'C' source line config statements
; CONFIG1
config FOSC = INTRC_NOCLKOUT; Oscillator Selection bits (INTOSCIO oscillator: I/O function on RA6/OSC2/CLKOUT pin, I/O function on RA7/OSC1/CLKIN)
config WDTE = OFF ; Watchdog Timer Enable bit (WDT disabled and can be enabled by SWDTEN bit of the WDTCON register)
config PWRTE = OFF ; Power-up Timer Enable bit (PWRT disabled)
config MCLRE = ON ; RE3/MCLR pin function select bit (RE3/MCLR pin function is MCLR)
config CP = OFF ; Code Protection bit (Program memory code protection is disabled)
config CPD = OFF ; Data Code Protection bit (Data memory code protection is disabled)
config BOREN = OFF ; Brown Out Reset Selection bits (BOR disabled)
config IESO = ON ; Internal External Switchover bit (Internal/External Switchover mode is enabled)
config FCMEN = OFF ; Fail-Safe Clock Monitor Enabled bit (Fail-Safe Clock Monitor is disabled)
config LVP = OFF ; Low Voltage Programming Enable bit (RB3 pin has digital I/O, HV on MCLR must be used for programming)
; CONFIG2
config BOR4V = BOR40V ; Brown-out Reset Selection bit (Brown-out Reset set to 4.0V)
config WRT = OFF ; Flash Program Memory Self Write Enable bits (Write protection off)
;
; Power-On-Reset entry point
;
PSECT Por_Vec,global,class=CODE,delta=2
global resetVec
resetVec:
PAGESEL main ;jump to the main routine
goto main
;
; Data space use by interrupt handler to save context
PSECT Isr_Data,global,class=RAM,space=1,delta=1,noexec
;
GLOBAL WREG_save,STATUS_save
;
WREG_save: DS 1
STATUS_save: DS 1
PCLATH_save: DS 1
;
; Interrupt vector and handler
PSECT Isr_Vec,global,class=CODE,delta=2
GLOBAL IsrVec
;
IsrVec:
movwf WREG_save
swapf STATUS,W
movwf STATUS_save
movf PCLATH,W
movwf PCLATH_save
;
IsrHandler:
;
IsrExit:
movf PCLATH_save,W
movwf PCLATH
swapf STATUS_save,W
movwf STATUS
swapf WREG_save,F
swapf WREG_save,F
retfie ; Return from interrupt
;
; Main application
;
PSECT MainCode,global,class=CODE,delta=2
main:
clrf INTCON ; disable all interrupts
banksel PIE1
clrf BANKMASK(PIE1)
clrf BANKMASK(PIE2)
banksel OSCCON ; Select INTOSC at 8MHz
movlw 0x70
movwf BANKMASK(OSCCON)
banksel ANSEL ; Make all GPIO us digital mode
clrf BANKMASK(ANSEL)
clrf BANKMASK(ANSELH)
banksel PORTA ; Make all output zero
clrf BANKMASK(PORTA)
clrf BANKMASK(PORTB)
clrf BANKMASK(PORTC)
banksel TRISA ; Select input and output GPIOs
clrf BANKMASK(TRISA) ; Make RA0-RA7 outputs
movlw 0x01
movwf BANKMASK(TRISB) ; Make RB0 an input, RB1-RB7 outputs
clrf BANKMASK(TRISC) ; Make all PORTC outputs
banksel OPTION_REG
movlw 0xDF
movwf BANKMASK(OPTION_REG) ; Set TIMER0 clock source to FOSC/4, prescale 1:1, WDT prescale 1:128
;
;
;
banksel WDTCON ; Enable WDT timeout
bsf BANKMASK(WDTCON),WDTCON_SWDTEN_POSITION
loop:
banksel PORTA
movlw 0x01
xorwf PORTA,F
sleep ; typical sleep time 2.048 seconds
nop
pagesel loop
goto loop
;
; Tell linker the power on reset entry point
;
END resetVec
Another thing that may help or brick your PICkit4 is to use the MPLABX Integrated-Programming-Environment(IPE) tool to do a "Hardware Tool Emergency Boot Firmware Recovery".
This is a tricky process that may require a few tries before you do it correctly. You will need to unplug and plug in the PICkit4 at the proper steps in the process.
The worst case for you is that your MPLABX v5.40 installation is somehow corrupt. This will require you to uninstall it, be sure that any remnants of previous MPLABX installs have been deleted, the install it all again. After doing the only 10 or 15 times it becomes only monstrously annoying.